[ARM] S3C64XX: Add IRQ_EINT support

Add the necessary code to support IRQ_EINT(x) on
the S3C64XX series of CPUs.

Note, since there is no GPIO configuration support
in the kernel, the irq set_type method does not
configure the relevant pin to interrupt.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

arch/arm/plat-s3c64xx/Makefile

@@ -15,6 +15,7 @@ obj-				:=
 obj-y				+= dev-uart.o
 obj-y				+= cpu.o
 obj-y				+= irq.o
+obj-y				+= irq-eint.o
 obj-y				+= clock.o
 
 # CPU support

arch/arm/plat-s3c64xx/include/plat/irqs.h

@@ -150,7 +150,8 @@
 
 #define S3C_IRQ_EINT_BASE	S3C_IRQ(64+5)
 
-#define S3C_EINT(x)	((x) + S3C_IRQ_EINT_BASE)
+#define S3C_EINT(x)		((x) + S3C_IRQ_EINT_BASE)
+#define IRQ_EINT(x)		S3C_EINT(x)
 
 /* Define NR_IRQs here, machine specific can always re-define.
  * Currently the IRQ_EINT27 is the last one we can have. */

arch/arm/plat-s3c64xx/irq-eint.c

@@ -0,0 +1,202 @@
+/* arch/arm/plat-s3c64xx/irq-eint.c
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *      http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX - Interrupt handling for IRQ_EINT(x)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+
+#include <asm/hardware/vic.h>
+
+#include <plat/regs-irqtype.h>
+
+#include <mach/map.h>
+#include <plat/cpu.h>
+
+/* GPIO is 0x7F008xxx, */
+#define S3C64XX_GPIOREG(x)	(S3C64XX_VA_GPIO + (x))
+
+#define S3C64XX_EINT0CON0	S3C64XX_GPIOREG(0x900)
+#define S3C64XX_EINT0CON1	S3C64XX_GPIOREG(0x904)
+#define S3C64XX_EINT0FLTCON0	S3C64XX_GPIOREG(0x910)
+#define S3C64XX_EINT0FLTCON1	S3C64XX_GPIOREG(0x914)
+#define S3C64XX_EINT0FLTCON2	S3C64XX_GPIOREG(0x918)
+#define S3C64XX_EINT0FLTCON3	S3C64XX_GPIOREG(0x91C)
+
+#define S3C64XX_EINT0MASK	S3C64XX_GPIOREG(0x920)
+#define S3C64XX_EINT0PEND	S3C64XX_GPIOREG(0x924)
+
+
+#define eint_offset(irq)	((irq) - IRQ_EINT(0))
+#define eint_irq_to_bit(irq)	(1 << eint_offset(irq))
+
+static inline void s3c_irq_eint_mask(unsigned int irq)
+{
+	u32 mask;
+
+	mask = __raw_readl(S3C64XX_EINT0MASK);
+	mask |= eint_irq_to_bit(irq);
+	__raw_writel(mask, S3C64XX_EINT0MASK);
+}
+
+static void s3c_irq_eint_unmask(unsigned int irq)
+{
+	u32 mask;
+
+	mask = __raw_readl(S3C64XX_EINT0MASK);
+	mask |= eint_irq_to_bit(irq);
+	__raw_writel(mask, S3C64XX_EINT0MASK);
+}
+
+static inline void s3c_irq_eint_ack(unsigned int irq)
+{
+	__raw_writel(eint_irq_to_bit(irq), S3C64XX_EINT0PEND);
+}
+
+static void s3c_irq_eint_maskack(unsigned int irq)
+{
+	/* compiler should in-line these */
+	s3c_irq_eint_mask(irq);
+	s3c_irq_eint_ack(irq);
+}
+
+static int s3c_irq_eint_set_type(unsigned int irq, unsigned int type)
+{
+	int offs = eint_offset(irq);
+	int shift;
+	u32 ctrl, mask;
+	u32 newvalue = 0;
+	void __iomem *reg;
+
+	if (offs > 27)
+		return -EINVAL;
+
+	if (offs > 15)
+		reg = S3C64XX_EINT0CON0;
+	else
+		reg = S3C64XX_EINT0CON1;
+
+	switch (type) {
+	case IRQ_TYPE_NONE:
+		printk(KERN_WARNING "No edge setting!\n");
+		break;
+
+	case IRQ_TYPE_EDGE_RISING:
+		newvalue = S3C2410_EXTINT_RISEEDGE;
+		break;
+
+	case IRQ_TYPE_EDGE_FALLING:
+		newvalue = S3C2410_EXTINT_FALLEDGE;
+		break;
+
+	case IRQ_TYPE_EDGE_BOTH:
+		newvalue = S3C2410_EXTINT_BOTHEDGE;
+		break;
+
+	case IRQ_TYPE_LEVEL_LOW:
+		newvalue = S3C2410_EXTINT_LOWLEV;
+		break;
+
+	case IRQ_TYPE_LEVEL_HIGH:
+		newvalue = S3C2410_EXTINT_HILEV;
+		break;
+
+	default:
+		printk(KERN_ERR "No such irq type %d", type);
+		return -1;
+	}
+
+	shift = (offs / 2) * 4;
+	mask = 0x7 << shift;
+
+	ctrl = __raw_readl(reg);
+	ctrl &= ~mask;
+	ctrl |= newvalue << shift;
+	__raw_writel(ctrl, reg);
+
+	return 0;
+}
+
+static struct irq_chip s3c_irq_eint = {
+	.name		= "s3c-eint",
+	.mask		= s3c_irq_eint_mask,
+	.unmask		= s3c_irq_eint_unmask,
+	.mask_ack	= s3c_irq_eint_maskack,
+	.ack		= s3c_irq_eint_ack,
+	.set_type	= s3c_irq_eint_set_type,
+};
+
+/* s3c_irq_demux_eint
+ *
+ * This function demuxes the IRQ from the group0 external interrupts,
+ * from IRQ_EINT(0) to IRQ_EINT(27). It is designed to be inlined into
+ * the specific handlers s3c_irq_demux_eintX_Y.
+ */
+static inline void s3c_irq_demux_eint(unsigned int start, unsigned int end)
+{
+	u32 status = __raw_readl(S3C64XX_EINT0PEND);
+	u32 mask = __raw_readl(S3C64XX_EINT0MASK);
+	unsigned int irq;
+
+	status &= ~mask;
+	status >>= start;
+	status &= (1 << (end - start + 1)) - 1;
+
+	for (irq = IRQ_EINT(start); irq <= IRQ_EINT(end); irq++) {
+		if (status & 1)
+			generic_handle_irq(irq);
+
+		status >>= 1;
+	}
+}
+
+static void s3c_irq_demux_eint0_3(unsigned int irq, struct irq_desc *desc)
+{
+	s3c_irq_demux_eint(0, 3);
+}
+
+static void s3c_irq_demux_eint4_11(unsigned int irq, struct irq_desc *desc)
+{
+	s3c_irq_demux_eint(4, 11);
+}
+
+static void s3c_irq_demux_eint12_19(unsigned int irq, struct irq_desc *desc)
+{
+	s3c_irq_demux_eint(12, 19);
+}
+
+static void s3c_irq_demux_eint20_27(unsigned int irq, struct irq_desc *desc)
+{
+	s3c_irq_demux_eint(20, 27);
+}
+
+int __init s3c64xx_init_irq_eint(void)
+{
+	int irq;
+
+	for (irq = IRQ_EINT(0); irq <= IRQ_EINT(27); irq++) {
+		set_irq_chip(irq, &s3c_irq_eint);
+		set_irq_handler(irq, handle_level_irq);
+		set_irq_flags(irq, IRQF_VALID);
+	}
+
+	set_irq_chained_handler(IRQ_EINT0_3, s3c_irq_demux_eint0_3);
+	set_irq_chained_handler(IRQ_EINT4_11, s3c_irq_demux_eint4_11);
+	set_irq_chained_handler(IRQ_EINT12_19, s3c_irq_demux_eint12_19);
+	set_irq_chained_handler(IRQ_EINT20_27, s3c_irq_demux_eint20_27);
+
+	return 0;
+}
+
+arch_initcall(s3c64xx_init_irq_eint);